1. Field of the Invention
Aspects of the present invention relate to an agitator, and more particularly, to an agitator that electrifies a developer with friction, a developing apparatus having the agitator, and an image forming device having the agitator.
2. Description of the Related Art
An image forming device, such as a printer, that uses an electrophotography process, is an apparatus, which forms an electrostatic latent image on a photoconductor using a light exposing unit, develops the electrostatic latent image with a developer by using a developing apparatus to form a developer image, and then transfers and fixes the developer image onto a printing medium.
The developer, which is used for developing the electrostatic latent image in the developing apparatus, is either a one-component system developer or a two-component system developer. In case of the one component system developer, toner particles are electrified by friction with themselves or friction with a charging member. The electrified toner particles are moved onto a developing roller and then attached to an electrostatic latent image region of the photoconductor to form a developer image.
A two-component system developer is a developer in which magnetic carrier particles are mixed with non-magnetic toner particles made of synthetic resins. The toner particles are electrified by friction with the carrier particles and with themselves. The electrified toner particles are moved onto the developing roller along with the carrier particles and then attached to an electrostatic latent image region of the photoconductor to form a developer image.
In general, a developing apparatus of an image forming device is provided with an agitator to electrify the toner particles of a developer by friction. A conventional agitator is shown in FIGS. 1A and 1B. As shown in FIG. 1A, the agitator 1 has a structure in which an agitating wing 3 is in the form of a helix on a rotary shaft 2. The agitator 1 rotates in a developer-containing space of a developer casing (not shown). As the agitating wing 3 rotates, toner particles and, if it is a two-component system, carrier particles are mixed with one another, and the toner particles are electrified by friction.
The longer the contact time of the toner particles, and in a two-component system, to the carrier particles and the greater the number of the toner particles contacted, the smoother the electrification of the toner particles that is achieved. To carry out a printing operation at a high speed, it is required that the toner particles be charged in a short time. However, for a conventional agitator to lengthen the contact time of the toner particles to the carrier particles or to increase the number of the toner particles contacted, the agitating wing 3 should be quickly rotated or the diameter thereof enlarged. To quickly rotate the agitating wing 3, a change to the design of the agitator driving system would be required, and to enlarge the diameter of the agitating wing 3 would require a layout change of the developing apparatus. Neither alternative is particularly desirable.